Hetian jade is one of the most important tremolite jade resources in the world, and Hetian is the most important jade locality in China. A study on oxygen and silicon isotope of the nephrite ore deposits has been stated in this paper. The analytical results show that the δ18O and δ30Si values of the nephrite ore deposit are distributed in a narrow range, which are all lower than the values of the host rocks. It is suggested that the nephrite ore deposits in Hetian and Xiuyan may be the magmatic hydrothermal replacement deposit, and the nephrite deposit of Manasi green jade may be the metamorphic ore deposit.